Mortality of Marbled Murrelets in Gill Nets in North America

Chapter 27 Mortality of Marbled Murrelets in Gill Nets in North America

Harry R. Carter1 Michael L.C. McAllister2 M.E. “Pete” Isleib3

Abstract: Mortality of Marbled Murrelets (Brachyramphus from a boat and are free to move with the currents, whereas marmoratus) due to accidental capture in gill nets is one of the set nets are anchored at both ends and can be set at any major threats to murrelet populations. Gill-net mortality of depth. Other forms of net fishing tend to be much less murrelets throughout their range has been occurring for several destructive to birds. Seine fishing is known at times to decades and probably has contributed to declines in populations, cause mortality. in conjunction with loss of nesting habitat and mortality from oil At-sea mortality from gill nets and oil spills has been spills. Gill-net mortality has been best studied in Prince William Sound, Alaska, and in Barkley Sound, British Columbia. How- identified as a significant conservation problem for the ever, gill-net fishing occurs widely and it is likely that: (1) Marbled Murrelet (Carter and Morrison 1992; U.S. Fish several thousand to tens of thousands of murrelets are killed and Wildlife Service, in press). Gill-net mortality may act annually in Alaska; (2) hundreds to thousands are probably killed separately or in concert with the loss of nesting habitat annually in British Columbia; and (3) tens to hundreds may be and mortality from oil pollution to threaten survival of killed annually in Washington. In the 1980’s, hundreds also were several populations. In this paper, we: (1) review factors killed in central California although recent regulations have mark- that lead to mortality of murrelets in gill nets; (2) discuss edly reduced this mortality. Despite the potential impacts of gill-net known and suspected levels of mortality of Marbled mortality on murrelet populations, little has been done to examine Murrelets in gill and seine nets throughout their range in the degree of mortality or to develop long-term solutions to reduce or eliminate net mortality. Gill-net mortality should be North America; and (3) indicate management actions that assessed by management agencies through the establishment of have been considered to stop or reduce the impacts of gill- more observer programs, especially in Alaska, British Columbia, net mortality. Information is presented by state and province and Washington. from north to south. Information for the three southern states was collated for the Marbled Murrelet Recovery Plan (U.S. Fish and Wildlife Service, in press.) Gill-net fisheries have occurred off the Pacific coast of western North America throughout this century. Following Alaska World War II, these fisheries expanded to cover large geographic areas, including most nearshore and offshore Large net fisheries have existed in many areas of Alaska waters. Concern has been expressed repeatedly over the last for decades. These fisheries target mainly salmon 3 decades about the excessive mortality of seabirds and (Onchorynchus sp.), although other fish also are taken (e.g., marine mammals in gill nets in many areas of the North herring Clupea harengus). Salmon fisheries are broken Pacific Ocean (see reviews in DeGange and others 1993; down into 12 statistical areas with many districts and Jones and DeGange 1988; King 1984; King and others 1979). subdistricts in each area. The salmon gill-net fishery targets Most attention has been paid to offshore international fisheries specific stocks of fish as they return to rivers to spawn, and where hundreds of thousands of seabirds are killed annually. can occur within 3 miles of land in a river, river delta, Less attention has been directed towards lower levels of embayment, or fjord. Open fishing periods vary between a mortality in nearshore gill-net fisheries, even though this half day and 7 days per week, depending on run strength of mortality can have serious impacts to local seabird populations fish stocks, harvest levels, and numbers of fish reaching (Atkins and Heneman 1987; Carter and Sealy 1984; DeGange spawning areas. Some districts are opened for only one and others 1993; Piatt and Gould, in press; Piatt and others year out of five. 1984; Takekawa and others 1990). There has been mounting concern about the impacts of Types of Nets gill-net mortality on the Marbled Murrelet (Brachyramphus Drift nets are about 900-1200 feet (275-365 m) long marmoratus) (Carter and Morrison 1992, Carter and Sealy and are fished as a single unit. Set nets are about 300-900 1984, DeGange and others 1993, Marshall 1988a, Sealy feet (90-275 m) long, but are usually broken down into and Carter 1984). Murrelets become tangled and drown in subunits as short as 60 feet (18 m) long. Gill nets in most gill nets while swimming under water. Gill-net fishing is areas are restricted to 60 meshes deep. In Bristol Bay, there conducted with either drift or set nets. Drift nets are operated is a 28-meshes deep maximum for both set and drift nets. Stretched mesh sizes vary from 4.5-9.0 inches (11.4-22.9 1 Wildlife Biologist, National Biological Service, U.S. Department cm) although restrictions apply in certain districts and at of the Interior, California Pacific Science Center, 6924 Tremont Road, certain times. Thus, a net with a mesh size of 5.5 inches (14 Dixon, CA 95620 cm), with 60 meshes, would be about 30 feet (9 m) deep. 2 Wildlife Biologist, Wildland Resources Enterprises, 60069 Morgan Lake Road, La Grande, OR 97850 When restrictions do not apply, nets are often set at 120-150 3 Commercial Fisherman, 9229 Emily Way, Juneau, AK 99801 meshes deep. Further discussion of various aspects relating (Deceased June 1993)

USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 271 Carter and others Chapter 27 Mortality in Gill Nets to how murrelets become tangled in gill nets can be found in He felt that the numbers had increased in the past 20 years Carter and Sealy (1984). due to several factors: the vessels are continuously fishing around the clock; the use of finer web; and more boats are Behavior Near Nets actively fishing (Isleib 1982). He observed that murrelets Isleib (1982) observed Marbled Murrelets feeding close are killed throughout the fishing season, with most (80+ to nets, as well as elsewhere, but birds appeared to be displaced percent) killed at night. by a vessel or activity aboard a vessel. Young of the year He felt that the major locations of kills were as follows. showed little fear of vessels. Isleib usually observed murrelets In the Copper and Bering River Districts, murrelets are not swimming along the nets in singles or pairs, frequently numerous, except during brief migration periods in early diving, often surfacing on one side and then the other of the September, and most birds occur offshore. These districts net. This occurs with nets 60 feet (18 m) deep, with mesh front the open Gulf of Alaska. Here, most murrelets are sizes of 5.5 inches (14 cm). Isleib suggested that they may caught between 0.5 and 3 miles (0.3-1.9 km) offshore, where actually be going through these nets, but more than 80 water depth is about 10 fathoms (18 m). His best estimate of percent of the birds were caught at night. Isleib felt murrelets murrelet mortality in these districts is from 100 to 300 are likely caught while pursuing small feed fishes, including annually. A similar number, or slightly higher mortality of juvenile herring, sand lance (Ammodytes hexapterus), capelin Common Murres (Uria aalge) also occurs here. (Mallotus villosus), needlefish (Strongylura exilis), and In the Coghill-Unakwik and Eshamy districts, murrelets various salmon fry. This may not be the case for some of the were numerous in the 1970s: 10,000+ Kittlitz’s Murrelets juvenile murrelet mortalities where juveniles tend to dive (Brachyramphus brevirostris) and 100,000+ Marbled from suspected danger on the surface while adults tend to Murrelets. These districts are either within or at the mouths fly. Murrelets are caught at varying depths in the nets, from of fjords. Isleib estimated the annual kill at about 500 birds. the surface to 10 meters, mostly 3 to 5 meters down. Beyond In the Bristol Bay area, murrelets are very rare. Isleib fished 60 meshes deep, murrelets do not appear to be caught. Bristol Bay for 3 years and only 3 Common Murres were killed in 1981. Historical Records of Mortality: 1950s to 1980s While the above observations apply mainly to the 1970s, Historical documentation of gill-net mortality of murrelets more recent comments by Isleib reflected similar or greater (and other seabirds) in Alaska before the 1970s is poor. An amounts of mortality continuing throughout the 1980s (see observer program for determining incidental mortality of DeGange and others 1993). For southeastern Alaska, Isleib seabirds in offshore net fisheries in Alaska began in 1974 had estimated in DeGange and others (1993) up to 1,000 (King and others 1979), but a similar observer program for Marbled Murrelets were taken annually, but it is unclear if nearshore waters, where murrelets primarily occur and are this estimate is based on more data than available in 1982. killed, was not instigated by the National Marine Fisheries At this time, he had “no first hand knowledge”, but suspected Service until 1990 in Prince William Sound (DeGange and mortality at similar levels as found in Prince William Sound others 1993, Mendenhall 1992, Wynne and others 1991). At (Isleib 1982). His suspicion was based on fishing effort, least 3 scraps of information indicate that gill-net mortality fishing locations near murrelet aggregations, and types of occurred in the 1950s and 1960s: (1) Sealy and Carter (1984) fishing gear (Isleib, pers. comm.). For the same reasons, he reported an adult murrelet in breeding plumage was killed at suspected similar mortality along the Alaska peninsula during a depth of 25-30 feet in a gill net near Little Port Walter on the 1970s and 1980s (Isleib, pers. comm.). Baranof Island in southeastern Alaska between 29 July and 6 Isleib observed that murrelets are captured in the same August 1958 (Sealy, pers. comm.); (2) a molting murrelet locations year after year throughout the season. Young of was reported killed in a fishing net at Coho Beach, in the the year, first noted in mid-July, are killed in a higher northern Gulf of Alaska, in August 1959 (Smith 1959); and proportion to their respective numbers than adults. (3) two adults in breeding plumage were killed in gill nets near Cordova, in the northern Gulf of Alaska, in 1969 (Carter, Historical Records of Mortality: 1980s and 1990s unpubl. data in Mendenhall 1992). From 1983-1993, one of us (McAllister, unpubl. data) In the 1970s, the only documentation of mortality of conducted surveys of murrelets throughout most coastal regions murrelets in gill nets in Alaska was obtained by one of us in the Gulf of Alaska. Preliminary population estimates for (Isleib). Below we summarize the information and the Gulf of Alaska are similar to estimates generated more observations, taken largely from a letter to the senior author recently from the Outer Continental Shelf Environmental (Isleib 1982). Most of Isleib’s observations are from Statistical Assessment Program (OCSEAP)(Piatt and Ford 1993; Piatt Area E, the Prince William Sound/Copper-Bering River and Naslund, this volume). The sub-area found to support the Districts. Specific districts have different opening periods greatest populations (45,000-70,000 birds [McAllister, unpubl. by gear type. data]) is Southeast Alaska. Three major nesting areas (each The number of murrelets that are killed is difficult to containing approximately 5,000-10,000 birds) occur in determine. Isleib estimated that the degree of magnitude for southeastern Alaska: the west slopes of Admiralty Island; the all the districts of Area E was “several hundreds” annually. mainland slopes of Stephens Passage (Juneau south to Tracy

272 USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. Carter and others Chapter 27 Mortality in Gill Nets

Arm); and the mainland slopes near Wrangell (Stikine River Inlet before being reduced by gill-net mortality and logging south to Ernest Sound). At-sea foraging areas occur near of nesting habitats in old-growth forests. Area 1F is an offshore these and other nesting areas, resulting in a complex pattern area where murrelets are not found in aggregations. In Areas of aggregations throughout much of southeastern Alaska (figs. 6A and 11B, large numbers of gill-net boats congregate 1 and 2). There are three fishing subdistricts where intensive from June through August, and these could have decimated gill-net fishing overlap with at-sea foraging aggregations of local populations. In Area 6A, dense murrelet foraging Marbled Murrelets: (1) Area 1B, located at the south end of aggregations occur at Point Baker and along the north shores Revillagigedo Channel near the Canadian border; (2) Area of Zarembo Island during gill-net openings. This would be a 6A, located near Point Baker in Sumner Strait; and (3) Area prime area in southeastern Alaska to monitor the ongoing 11B, located south of Juneau in the central part of Stevens impacts of gill-net fishing on the Marbled Murrelet. In Area Passage. Gill-net fisheries in subdistricts 6A and 11B are 11B, McAllister (unpubl. data) retrieved two floating dead targeted on fish stocks returning to the Stikine and Taku Marbled Murrelets in the vicinity of gill-net boats fishing at rivers, respectively. Area 1B receives the most fishing pressure Taku Harbor. A former gill-net fisherman reported to and is open for the longest period each year (June-October). McAllister that Marbled Murrelets were killed regularly in Although murrelets are not found to aggregate in large area 11B in the late 1970s, stating that up to 12 Marbled numbers in Area 1B at present, it is possible that large numbers Murrelets were found in nets upon retrieving gear at dawn formally occurred in Boca de Quadra, Behm Canal, and Carol near Taku Harbor in Area 11B. Murrelet mortality does not

Figure 1—North portion of Southeastern Alaska indicating 1988 fishing districts (numbered) with locations of Marbled Murrelet at-sea aggregations, potential old-growth forest nesting areas, and gill-net fishing areas (McAllister, unpubl. data). Murrelet information for Glacier Bay is not included.

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Figure 2—South portion of Southeastern Alaska indicating 1988 fishing districts (numbered). Other symbols and sources as in fig. 1. occur to a significant degree in subdistricts 15A and 15C in birds. Murrelets are frequently trapped inside encircled nets, southern Lynn Canal, because birds in this region forage to but almost always escape by swimming and hopping over or the south in northern Steven’s Passage and in Icy Straits. through spaces between the floats that line the top of nets. Also, gill-net fishing tends to occur in this subdistrict On five occasions in late summer, McAllister retrieved and mainly in July to October, after most birds have left the released live murrelets from encircled nets near Cape Chacon area. It is difficult to estimate the true magnitude of impact, in district 2 (fig. 2) that were not able to escape over the but when actively foraging aggregations of murrelets overlap floats, including juveniles and adults undergoing prebasic with gill-net gear, the potential for mortality is high (Carter molt. A seine fisherman has reported to McAllister similar and Sealy 1984). entrapment of murrelets in seine nets in August at Stepovak Purse seine fishing occurs more extensively than gill- Bay on the Alaska Peninsula. net fishing throughout most of Southeast Alaska. McAllister In Prince William Sound and Cook Inlet, Isleib (pers. (unpubl. data) has observed no mortalities of Marbled comm.) indicated continued mortality of Marbled Murrelets Murrelets in 10 years of fishing in the area, although fishermen in the 1980s and 1990s, at levels similar to or greater than have reported “dozens” of Common Murres and Rhinoceros that reported in the 1970s (DeGange and others 1993). In Auklets (Cerorhinca monocerata) per net and smaller numbers addition, Kuletz (pers. comm.) reported catching a few of Cassin’s Auklets (Ptychoramphus aleuticus) being killed murrelets per year from 1982-1988 during set-net fishing on in seine nets in a year, especially in fishing district 4 (fig. 2). the east side of the middle of Cook Inlet. This mortality This mortality could amount to many thousands of dead occurred while fishing with nine nets, set a few days per

274 USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. Carter and others Chapter 27 Mortality in Gill Nets week during the summer. Fishermen have reported further should be made to reduce this mortality to much lower levels. (DeGange, pers. comm.) that murrelets have been killed Carter and Sealy (1984) pointed out two main methods of occasionally near Raspberry Island at the northwest end of reducing gill-net mortality: (1) exclude fishing from areas Kupreanof Strait, involving mostly juveniles. In other areas with high murrelet densities at sea; and (2) allow daylight near Kodiak Island (e.g., Cape Uganik and the south side of fishing only, since most murrelets are caught in nets at night. Kupreanof Strait), none were known to be killed. A few These solutions often may not apply to other seabird species. murrelets per year also were reported killed in nets on the Another factor affecting levels of mortality is the future of east side of Cook Inlet near Clam Gulch (between Kenai and these fisheries themselves, if fish stocks decline. However, Homer). This mortality occurred during nine net sets over gill-net fishing is likely to continue at high levels due to the fishing season, whereas about 150 net sets occur in this climbing value of salmon, limited entry of fishermen, and area throughout the year. Puffins (Fratercula sp.) and other constant fishing pressure during openings. It is clear that gill- seabirds (possibly including murrelets) are taken occasionally net mortality has the potential to be the greatest conservation in nets set near Chisdik Island on the west side of Cook Inlet. problem for Marbled Murrelets in Alaska since it occurs However, no seabirds were reported killed in nets while annually throughout almost all at-sea foraging areas during fishing north of Chisdik Island. the breeding season when murrelets are aggregated. Since 1990, official observers were placed on fishing boats in Prince William Sound and near the Copper River British Columbia delta by the National Marine Fisheries Service (Mendenhall 1992). Observers reported mortalities of 36 and 25 Large salmon gill-net fisheries have existed off the mouth Brachyramphus murrelets (84 percent Marbled Murrelets) in of the Fraser River and in the Skeena River area since the 1990 and 1991 (Wynne and others 1991, 1992). Extrapolating turn of the century. In the 1950s, other large fisheries from observed fishing effort (3.9 percent and 3.5 percent nets developed in other parts of British Columbia as the Fraser observed in 1990 and 1991, respectively), then, as many as fishery declined, due to severe landslides and other problems 923 and 714 murrelets may have been killed in gill nets in upriver (Larkin and Ricker 1964). Small coastal fisheries Prince William Sound in 1990 and 1991, respectively (Piatt expanded with the development of a mobile fleet of gill-net and Naslund, this volume; Wynne and others 1991, 1992). boats that travelled widely in relation to regulated openings. Extrapolating 1990 data from mean catch per week data, The British Columbia gill-net and seine fishery is broken Wynne and others (1991) estimated that 1,468 seabirds (95 down into 32 statistical areas and subdistricts (figs. 3 and 4). percent confidence limits: 836-2,100) were killed in Prince Certain portions of these areas are closed to net fishing. Like William Sound in 1990, 97 percent of which were murrelets. Alaska, open fishing periods vary considerably within areas Using this level of observed mortality in Prince William and districts. Gill nets used have a 115-mm minimum mesh Sound, Piatt and Naslund (this volume) estimated annual size and vary from 100-500-m length maximum (Department mortality of 900, 1100, and 300 murrelets in Southeast Alaska, of Fisheries and Oceans Canada 1978). lower Cook Inlet, and along the Alaska Peninsula, respectively. Historical documentation of gill-net mortality of murrelets Thus, the Alaska total may approach about 3,300 birds and other seabirds in British Columbia is lacking. In 1979, annually. However, it is likely that gill-net mortality rates Marbled Murrelets were first reported in gill nets in Barkley differ in other areas, and it may be inappropriate to apply Sound on the west coast of Vancouver Island in Statistical mortality rates from Prince William Sound elsewhere. Area 23 (Carter and Sealy 1984, see below). It is likely that gill-net mortality has occurred widely and for many decades Offshore Mortality in British Columbia. Carter (unpubl. data) travelled widely Only one bird was reported killed in offshore high-seas around the coast of British Columbia while conducting seabird drift-net fishery near the western Aleutian Islands through surveys in 1974-1977 (e.g., Campbell and others 1990, 1988 (DeGange 1978, DeGange and others 1985, Mendenhall Vermeer and others 1983). From 4-7 July 1976, he noted 1992, Sealy and Carter 1984). However, murrelets do not two areas in the inside passage from Prince Rupert to Campbell usually occur far offshore, and there does not appear to be a River where many gill-net fishing boats and Marbled Murrelets significant problem in offshore fisheries. co-occurred: (1) between Namu and Fairmile Inlet in Fitz Hugh Sound in Statistical Area 8 (fig. 3; see brief reference Outlook in DeGange and others 1993); and (2) in Johnstone Strait, Additional observer programs are required to estimate west of Port Neville, in Statistical Area 12 (fig. 4). Mortality total mortality of Marbled Murrelets and other seabirds of murrelets probably has occurred in many areas of British throughout Alaska (see DeGange and others 1993). Effort Columbia, but has not been properly documented, except in should focus on American nearshore fisheries. In 1992, a Barkley Sound (below). United Nations resolution was passed which ended large- In 1979 and 1980, Carter and Sealy (1984) documented scale pelagic driftnet fisheries, and this problem appears to mortality of Marbled Murrelets in gill nets in Barkley Sound. be resolved for the time being. On the other hand, declining A total of 28 dead Marbled Murrelets (including 26 breeding populations of Marbled Murrelets in Alaska cannot sustain adults, 1 nonbreeder and 1 juvenile), 10 Common Murres and the apparent levels of mortality in fishing nets. Great efforts 1 Rhinoceros Auklet were recovered from 5 fishermen, a

USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 275 Carter and others Chapter 27 Mortality in Gill Nets

Figure 3—Fishing statistical areas in northern British Columbia (Source: Department of Fisheries and Oceans Canada).

276 USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. Carter and others Chapter 27 Mortality in Gill Nets —Fishing statistical areas in southern British Columbia (Source: Department of Fisheries and Oceans Canada). Figure 4

USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 277 Carter and others Chapter 27 Mortality in Gill Nets fisheries patrol boat, or were found floating in the water. All Areas in 1992 (table 1). Gill-net fishing occurred in almost birds were killed between 11 June and 17 July in multifilament all areas, but the largest gill-net fisheries (>2,000 days fished) nylon nets, 135-375 m in length, less than 10 m in depth, with occurred in Statistical Areas 3, 4, 9, 10, 12, 14, 21, and 23 in mesh sizes of 10-13 cm. Most murrelets were killed at night the general vicinity of the Southeast Alaska border, Prince off Cape Beale and south Trevor Channel near Bamfield Rupert, Rivers Inlet, Smith Inlet, Queen Charlotte/Johnstone where large numbers of boats (average about 70/census) straits, Comox/Qualicum, Pachena Point to Bonilla Point, fished in densities of 1-4 boats/km2. In the same area, Marbled and Barkley Sound, respectively (see figs. 3 and 4). Marbled Murrelets also occurred in large numbers (average about Murrelets occur throughout the coasts of British Columbia, 266/census) and in high densities (average 11.3 birds/km2). including almost all fishing Statistical Areas (Campbell and Murrelets also were observed in small flocks sitting and others 1990, Rodway and others 1992, Vermeer and others diving near nets during the day and may have been attracted 1983). At present, it is difficult to assess the overall degree to nets to feed on small fish. Other details on gill-net mortality of gill-net mortality in British Columbia, given incomplete in Barkley Sound can be found in Carter and Sealy (1984). knowledge of the at-sea distribution and population sizes. Carter and Sealy (1984) estimated a minimum of 175- However, hundreds to thousands of murrelets may be killed 250 murrelets were killed in 1980, representing 6.2 percent of annually due to the extensive nature of these fisheries the breeding population or 7.8 percent of the potential fall throughout the province. population. They pointed out that the long-term impacts of In five statistical areas (3, 4, 9, 10, and 23), extensive such mortality could be great, but the degree of impact depended fishing effort occurred in July when large numbers of murrelets upon continued high fishing effort in Barkley Sound. In August are feeding chicks at the nest, aggregate in high densities, 1987 and December 1989, local people in Bamfield indicated and may be more susceptible to mortality (Carter and Sealy that gill-net fishing had not occurred every year since 1980 1984, 1990). Notably, Barkley Sound is among these earlier (Carter, unpubl. data; see brief reference in DeGange and fisheries. Heavy gill-net fishing effort occurs mainly in the others 1993). Nonetheless, gill-net mortality may have fall (August to November) in many Statistical Areas (table contributed to the decline (>50 percent) of Marbled Murrelets 1) which may avert high levels of mortality. Murrelets are that has been estimated in Trevor Channel and Barkley Sound undergoing a flightless pre-basic molt during this period and between 1979-1980 and 1992-1994 (Burger, this volume b; tend to occur in lower densities and closer to shore in many Kelson, pers. comm.). However, a large decline (about 40 areas (Carter and Stein, this volume). percent) also has occurred in Clayoquot Sound, further west In 1992, extensive seine fishing effort tended to occur in on the west coast of Vancouver Island, where gill-net fishing conjunction with high gill-net fishing effort in most statistical does not occur (Kelson and others, in press). This decline in areas (table 1). However, in Barkley Sound in 1979-1980, Barkley Sound probably reflects losses of old-growth forest seine fishing occurred in a different area (with low densities habitat and mortality from the Nestucca oil spill, in addition to of murrelets) than where gill-net fishing occurred, apparently gill-net mortality (Burger, this volume b; Carter and Kuletz, to prevent interference. Seabird mortality (primarily Common this volume; Rodway and others 1992). The decline in Clayoquot Murres) in seine nets did occur in the fall in Trevor Channel Sound has been attributed mainly to the loss of nesting habitats when gill-net fishing had moved farther up the Alberni Canal in old-growth forests (Kelson and others, in press). and seine fishing occurred in central Trevor Channel (Carter Marbled Murrelets were not recovered from purse seines and Sealy 1984). in Barkley Sound in 1979-1982, although hundreds of Gill-net and seine fisheries should be examined Common Murres were recovered (Carter, unpubl. data in throughout British Columbia for bycatch of Marbled Murrelets DeGange and others 1993). Similarly, murrelets were not and other seabirds. Extensive mortality may be occurring observed among floating carcasses of Common Murres off annually in many areas. Efforts should be taken to reduce or Carmanah Point north of Cape Flattery on the west coast of stop such mortality immediately. Vancouver Island in Statistical Areas 20, 21, and 121 in August 1979 (Carter, unpubl. data in Vermeer and Sealy Washington 1984; DeGange and others 1993). Marbled Murrelets were not reported among Ancient Murrelets (Synthliboramphus In Puget Sound and the Columbia River area (fig. 5), antiquus) and Rhinoceros Auklets killed in gill nets in July large gill-net and purse seine fisheries, which target several 1970-1971 and 1978 near Langara Island in the Queen species of salmon, have existed since at least the 1940s. Charlotte Islands (Statistical Area 1)(Vermeer and Sealy These fisheries peaked in the 1970s and 1980s and have 1984). However, Marbled Murrelets were caught frequently recently declined because of reduced catch, increasing on sports fishing lures near Campbell River in the 1960s regulation, and declining salmon populations. These fisheries (Campbell 1967). In 1979-1980, sports fishermen in Barkley involve both native and non-native fishermen and are managed Sound also reported catching murrelets on sports fishing by state (Washington Department of Fish and Wildlife lures (Carter, unpubl. data). [WDFW]) and federal (National Marine Fisheries Service To examine the potential for gill-net mortality of Marbled [NMFS]) agencies, native nations, and tribal (Northwest Murrelets in British Columbia, we have summarized recent Tribal Fish Commission) and non-tribal (Bureau of Indian data on gill-net and seine fishing effort for all Statistical Affairs [BIA]) fishing groups.

278 USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. Carter and others Chapter 27 Mortality in Gill Nets

Table 1—Fishing effort in boat-days fished for gill-nets (G) and seine-nets (S) in various fishery statistical areas on the Northern and Southern coasts of British Columbia by month in 1992 (Source: Department of Fisheries and Oceans Canada 1992). No gill- or seine- net fishing occurred from January to March 1992

Month Statistical area1 Fishing gear Apr May Jun Jul Aug Sep Oct Nov Dec Total effort Northern British Columbia 1 G 36 63 22 121 S 76 123 40 239 2E G 762 2 764 S 259 259 2W G 3 29 32 S433881 3 G 10 3,168 808 157 4,143 S 738 563 1,301 4 G 5 8,681 3,700 211 12,597 S 145 251 396 5 G 249 151 400 S 68 63 131 6G 519 24 S 133 69 202 7 G 32 46 178 256 S 5 10 109 124 8 G 156 840 175 21 1,192 S 737 127 864 9 G 3,412 322 3,734 S 0 10 G 5,676 365 6,041 S 0 30 G 0 S 0 Taku River2 G 25 180 121 1 327 S 0 Stikine River2 G 150 80 30 260 S 0 Southern British Columbia 11 G 1 1,884 1,885 S 0 12 G 5 32 3,695 923 2,279 7 6,941 S 866 294 306 39 1,505 13 G 285 228 951 1,464 S 281 154 369 804 14 G 980 1,378 2,358 S 186 186 15 G 0 S 0 16 G 900 68 43 1,011 S70171 17 G 301 41 342 S 0 18 G 2 954 65 1,021 S 0 19 G 0 S 0 20 G 8 70 1,607 4 1,689 S 1,185 1,185 21 G 3 2 2,620 2,625 S 1,475 1,475

(continues)

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Table 1—continued

Month Statistical area1 Fishing gear Apr May Jun Jul Aug Sep Oct Nov Dec Total effort

22 G 0 S 0 23 G 2,560 79 3 2,625 S 21 181 202 24 G 0 S 0 25 G 2 4 523 683 1,212 S 0 26 G 0 S 0 27 G 1 1 S 0 Fraser River3 G 14 20 31 104 2,446 56 526 53 7 3,257 S 0

Total G 14 20 240 25,198 16,757 3,146 8,416 2,476 72 56,339 S 0 0 0 1,966 3,827 856 2,151 225 0 9,025

1See figs. 3 and 4 for locations of statistical areas 2These rivers reach the ocean in southeastern Alaska 3Includes areas 28, 29A-E in fig. 4

Seabirds have been known to die in these fisheries for Pacific Salmon Commission - In 1993, a test fishery some time, although there has been little documentation of using monofilament gill nets was conducted at the south the degree of mortality (DeGange and others 1993, Speich entrance to the San Juan Islands (off San Juan and Lopez and Wahl 1989, Wahl 1981). Observer programs for marine islands) by the Pacific Salmon Commission, a Canadian- mammal bycatch in certain fisheries have been in place since based fisheries group (Craig and Cave 1994). Fishing occurred the 1970s, but there was little focus on seabirds. Speich and between dusk and dawn from 23 June to 7 August. One Wahl (1989) reported that Western Grebes (Aechmophorus murrelet was caught on 4 July 1993 off Iceberg Point, Lopez occidentalis), Common Murres, and Marbled Murrelets were Island. Another murrelet was caught in a gill net during test frequently killed, based on reports by local fishermen (Speich, fishing in this area in 1990, but no other details were provided. pers. comm.; Wahl, pers. comm.). Because significant mortality Most test fishing occurred further offshore than where most of murrelets was recorded in nearby Barkley Sound, British murrelets were observed foraging. Thus, more murrelets Columbia (see above), it is reasonable to assume that murrelet may be killed than indicated by this sample. A total of 64 mortality occurs in Washington waters also. Common Murres and 9 Rhinoceros Auklets also were killed Marbled Murrelets occur throughout most of northern in 1993. A similar program will occur in 1994. Puget Sound and the San Juan Islands where the bulk of the Washington Department of Fish and Wildlife - In 1993, Washington breeding population occurs (Speich and others a limited gill-net monitoring program for non-tribal fisheries 1992; Speich and Wahl, this volume; Wahl and others 1981). was conducted by WDFW in certain parts of Puget Sound Recent concern about the potential impacts of net fisheries where high concentrations of seabirds occur but few murrelets. on Marbled Murrelets in Washington prompted the U.S. A preliminary report is presented in a Biological Assessment Fish and Wildlife Service, U.S. Department of Interior, NMFS, (WDFW 1994). No murrelets were encountered, but 42 dead and BIA to develop additional tribal and non-tribal fishery birds, mainly Common Murres, were recorded. A more observer programs in 1993 to better assess impacts to seabirds, extensive program is planned for 1994. especially Marbled Murrelets (see U.S. Fish and Wildlife Purse Seine Vessel Owners Association - In 1993, two Service 1993b,c). Information on seabird mortality from Marbled Murrelets among about 50 seabirds were noted caught non-native fisheries in 1993 is just now becoming available, during the Seabird Observer Program for the Non-Tribal whereas some 1993 data from tribal fisheries have not been Purse Seine Fishery (Natural Resources Consultants 1993). released. Below, we summarize what information is available A total of 702 net sets were observed (about 3.9 percent of all to date, as collated for the Marbled Murrelet Recovery Plan non-tribal purse seine effort) in many areas from the Canadian (U.S. Fish and Wildlife Service, in press): border, through the San Juan Islands, to southern Puget Sound

280 USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. Carter and others Chapter 27 Mortality in Gill Nets and Hood Canal. Common Murres and Rhinoceros Auklets effort that occurs throughout this area is likely to cause were the most frequently caught species. On 25 August 1993, mortality on the scale of tens to hundreds of murrelets at a two murrelets were captured at 0657 hrs in the same purse minimum. Mortality extrapolations using 1979-1980 seine set about 500 m off Village Point, Lummi Island, in the mortality rates in relation to fishing effort and murrelet San Juan Islands. Both birds were captured alive and released densities from Trevor Channel in Barkley Sound, British within 10-15 minutes. Almost all seabirds captured during Columbia (Carter, unpubl. data; Carter and Sealy 1984), in this program also were released shortly after capture. A association with murrelet densities and fishing effort in similar program is envisioned for 1994. various fishing areas in northern Puget Sound and around Point Roberts Tribal Fishery - In February and March the San Juan Islands (Speich and others 1992; Speich and 1993, a small tribal fishery (involving 10 boats) for herring Wahl, this volume; Wahl and others 1981), yielded potential occurred in the Point Roberts/Semiahmoo Bay area. annual mortality estimates in the high hundreds (Wilson, Observers reported no entanglements or mortalities of pers. comm.). However, fishing effort is more intensive murrelets (BIA 1993). and murrelet densities are lower in northern Puget Sound Beached Birds - Kaiser (1993) reported two dead juvenile which may act to produce different mortality rates than murrelets and hundreds of other seabirds, especially Common observed in Barkley Sound. Observer programs should be Murres and Rhinoceros Auklets, washed ashore in Boundary continued and augmented to better describe gill-net mortality Bay, British Columbia, in August 1993. Boundary Bay is in northern Washington. located just across the border from areas where high numbers of murrelets and gill-net fishing areas co-occur. Oregon Grays Harbor - No Marbled Murrelets have been recorded as killed in gill nets in Grays Harbor during observer programs Gill-net fishing has been prohibited in estuaries, bays in summer and fall 1991, 1992, and 1993 for non-tribal and along the outer coast of Oregon since 1942 (Nelson and fisheries (Jefferies and Brown 1993, WDFW 1994). Between others 1992). No net-caused mortalities of murrelets are 4 and 10 percent of nets were monitored each season and known in Oregon. year. Bycatch included Common Murres, Rhinoceros Auklets, and loons. Some unidentified alcids and birds were recorded California which may have included murrelets. Willapa Bay - No Marbled Murrelet bycatch was observed Nearshore gill- and trammel-net fisheries have existed in Willapa Bay during observer programs in summer and fall in Central and Southern California since the early 1900s, 1991, 1992, and 1993 for non-tribal fisheries (Jefferies and and increased dramatically in size during the 1970s and Brown 1993, WDFW 1994). Between 1 and 13 percent of 1980s. These fisheries have targeted a wide array of fish, nets were monitored each season and year. Bycatch included including halibut and flounder (Bothidae and Pleuronectidae), Common Murres, cormorants, loons, grebes, and other alcids. croaker (Sciaenidae), shark, rockfish (Scorpaenidae), and Some unidentified alcids and birds were recorded which others. The catch from these fisheries peaked during the may have included murrelets. 1980s and early 1990s, but has since declined because of Columbia River - No Marbled Murrelets have been regulations aimed at reducing mortality of marine birds and recorded as killed in gill nets in the Columbia River during mammals. These fisheries are managed primarily by the observer programs in winter 1991, 1992 and 1993 (Jefferies California Department of Fish and Game (CDFG) which and Brown 1993). Bycatch included Common Murres, operated a bycatch monitoring program from 1983 to 1989. cormorants, Western and unidentified grebes, and Surf Scoters This observer program has been continued by NMFS from (Melanitta perspicillata). Some unidentified alcids and birds 1990 to 1994. These fisheries are managed through a series were reported which may have included murrelets. of CDFG fishing regions (fig. 5). With available information, it is not yet possible to Northern California - Gill-net fishing is prohibited north accurately determine the extent of mortality on Marbled of Point Reyes, Marin County. Murrelets in Washington. U.S. Fish and Wildlife Service Central California - Small numbers of birds were killed (1993b,c) stated in a biological opinion that a mortality of in gill nets before the late 1970’s (Sowls and others 1980). less than ten murrelets recovered from nets during the From 1979 to 1987, more than 70,000 Common Murres were observer programs would not jeopardize the continued killed in regions 3 and 4 (fig. 5), mainly in the summer and existence of the Marbled Murrelet in Washington. Additional fall, which contributed to a severe decline in the local breeding information on mortality must be derived from tribal and population (Carter and others 1992, DeGange and others non-tribal fisheries, especially within and north of the San 1993, Takekawa and others 1990). Thousands of other seabirds Juan Islands, northern Puget Sound, along the northern side including Marbled Murrelets, and marine mammals also were of the Olympic Peninsula, and in the Cape Flattery area. killed. Carter and Erickson (1988, 1992; also see Sealy and It is likely that significant mortality of murrelets is Carter 1984) summarized known evidence of mortality of occurring and has occurred in northern Puget Sound and murrelets from this fishery. Three birds were noted in the around the San Juan Islands. The large amount of fishing monitoring program: (1) two birds in Monterey Bay on 3

USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 281 Carter and others Chapter 27 Mortality in Gill Nets

Figure 5—Locations of gill-net fisheries along the coasts of California, Oregon and Washington. Numbers refer to fishing areas referred to in the text. In central and southern California, numbers 3, 4, 5, and 6 refer to California Department of Fish and Game fishing districts D10, D17, D18, and D19/D20, respectively.

December 1981; and (2) one bird off San Gregorio Creek, closed waters less than 40 fathoms (80 m) in regions 3 and San Mateo County, on 21 November 1986. More than 100 4A (fig. 5) to gill-net fishing. These regulations eliminated dead murrelets also were found on beaches in the Monterey most fishing in these areas, although a small gill-net fishery Bay area (regions 4A and 4B)(fig. 5) during the winter of for rockfish still exists outside of the Farallon Islands. Fishing 1980-1981. Carter and Erickson (1988, 1992) estimated that was further restricted in the Monterey Bay and south-central at least 150 to 300 birds were killed from 1979 to 1987. coast area in 1990 to further reduce mortality of marine A series of small, patchwork fishing closures were mammals (especially sea otters Enhydra lutra) and seabirds. implemented by CDFG from 1982 to 1984 in an attempt to Fishing was prevented in waters shallower than 30 fathoms reduce seabird mortality. These efforts proved to be (60 m), as well as in much of inner Monterey Bay, in regions ineffective. Following consideration of the problem for several 4B and 5A (fig. 5). years (Atkins and Heneman 1987, Salzman 1989), severe Most murrelets from the Central California population restrictions were implemented by CDFG in 1987 which (that nest in San Mateo and Santa Cruz counties) forage

282 USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. Carter and others Chapter 27 Mortality in Gill Nets throughout the year in waters less than 80 m in depth in Even the very few dead murrelets reported anecdotally regions 3 and 4A, or in waters less than 60 m in region 4B or from observer programs probably are significant because (fig. 5). Thus, 1987 and 1990 CDFG regulations should few people (aside from fishermen) could report mortalities, protect most birds from future gill-net mortality. No mortalities carcasses are discarded shortly after death and either sink or of Marbled Murrelets that could be related to gill-net fishing are taken by predators soon thereafter, fishermen typically have been recorded since 1987. However, murre mortality do not divulge knowledge of such mortality due to fear of has continued in winter in northern Monterey Bay, especially affecting their livelihoods, and only a small fraction of nets south of Año Nuevo State Reserve between Waddell Creek are examined in certain localities during monitoring programs. and Santa Cruz (near the border of regions 4A and 4B). For example, in Monterey Bay, California, only two birds Westfall (pers. comm.) also reported mortality of several were noted in the observer program, whereas more than 100 Marbled Murrelets on sports fishing lines near Santa Cruz. were found on nearby beaches and 150-300 birds were This mortality is important because of the small size and estimated killed over several years in the early 1980s (Carter poor health of the central California population (Carter and and Erickson 1992). Similarly, Carter and Sealy (1984) Erickson 1992). recovered only 28 dead murrelets, but fishermen reported Southern California - From 1983 to 1989, several thousand catching larger numbers and a minimum of 175-250 murrelets cormorants (mainly Brandt’s Cormorants, Phalacrocorax were estimated to have been killed in 1980 in Barkley Sound, penicillatus) probably were killed in gill-net fisheries in British Columbia. We feel that the large size of gill-net Southern California (Carter, unpubl. data). Mortalities were fisheries, and their extensive coverage of almost all coastal recorded both near the northern Channel Islands, as well as areas throughout the range of the Marbled Murrelet, places along the mainland coast, in regions 5B and 6. Because of gill-net mortality among the most significant problems for concerns by several interest groups, gill-net fishing was the species. prohibited in state waters within 3 miles of shore in these We suggest that a detailed examination of Marbled regions by CDFG regulations in January 1994, except for Murrelet and other seabird mortality in all coastal gill-net some areas near the northern Channel Islands, where fishing and seine fisheries is required throughout the range of the is still allowed outside of 1-2 miles from islands. murrelet, especially in Alaska, British Columbia, and No mortality of Marbled Murrelets that could be attributed Washington. It is likely that relatively minor modifications to gill-net and trammel-net fishing has been recorded south can be made to gill-net fisheries to vastly reduce mortality of Monterey Bay. Small numbers of murrelets occur in quickly without significant impact to fisheries, by either nearshore waters in this area during winter. These birds stopping fishing in small at-sea areas where murrelets are probably represent some limited southward dispersal of birds aggregated, preventing night fishing in certain areas, or both. in the non-breeding season from the Central California Similarly, mortality or injury in seine nets probably can be breeding population. Marbled Murrelets have not been greatly reduced by ensuring that spaces occur between floats recorded at the Channel Islands. along the top of the nets which allow murrelets and other seabirds to escape from encircled nets. If populations become Discussion (or are) too small, even low levels of gill-net and seine-net mortality or injury will have or has a greater relative effect. Mortality in gill nets may be one of the greatest Under these conditions, it may be necessary to stop all conservation problems facing the Marbled Murrelet. In Alaska mortality by considering more drastic changes, including and British Columbia, levels of mortality need to be better stopping gill-net fishing in much larger areas, changing established, but available evidence indicates that several fishing methods altogether, or both. To avoid severe thousands are killed annually. The large numbers of murrelets confrontation in the future, it is clear that this issue should killed in nets in Alaska and British Columbia has not been be addressed immediately. fully appreciated in previous reviews (DeGange and others 1993, Mendenhall 1992, Rodway and others 1992, Sealy Acknowledgments and Carter 1984). Since these levels of mortality probably have been focused on certain populations over the past few J. Engbring (U.S. Fish and Wildlife Service), C. Haugen, decades, gill-net mortality alone may have already been an M. Vojkovich, and P. Wild (California Department of Fish important factor of the decline in Alaska and British Columbia and Game), and D. McMullin, S. Benoit, and K. Lorette populations. Coupled with the loss of old-growth forest (Department of Fisheries and Oceans Canada) provided many nesting habitats and mortality from oil spills which may valuable reports and comments. Additional information was affect the same populations, it is clear that survival of provided by R. Brown, T. Clockson, A.R. DeGange, C. populations in many areas in the center of its range may be Haugen, S. Jefferies, K. Kuletz, G.S. Miller, J.F. Piatt, J. difficult if such problems continue. Lower numbers of birds Scordino, S.G. Sealy, S. Speich, T. Wahl, P. Wild, and J. killed in central California and Washington also have had Wilson. G. McChesney and L.L. Long assisted figure relatively large impacts on these small populations and may preparations. This summary has benefitted from reviews and have contributed significantly to their potential future editing by A.R. DeGange, L.L. Long, J.F. Piatt, C.J. Ralph, extirpation (see Carter and Erickson 1992). and M.G. Raphael.

USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 283 284 USDA Forest Service Gen. Tech. Rep. PSW-152. 1995.